Wear parts, particularly in the excavating industry, are usually composed of separable components so as to minimize the amount of material that must be replaced when the wear member becomes worn. As an example, excavating teeth are secured along the digging edge of excavating buckets to penetrate and break up the ground in advance of the bucket to improve the collection of earthen material and to protect the digging edge from premature wear. Such teeth usually comprise an adapter, a point or tip, and a lock or retainer to removably secure the point to the adapter.
An adapter is a base component that is fixed to the digging edge of an excavator by welding, mechanical attachment or being cast as an integral portion of the bucket lip. The adapter itself may have multiple parts, particularly in larger sized teeth, but is commonly a single component. In any event, the adapter includes a forwardly projecting nose as a mount for the wear member. The point has a generally wedge-shaped configuration with top and bottom walls that converge to a digging edge. The base or rear end of the point includes a rearwardly opening socket by which the point is received over the adapter nose. The lock is inserted into a passage that is collectively defined by aligned openings in the adapter nose and the point. The passage may extend through a central portion of the tooth, either vertically or horizontally, or be defined externally of the nose to receive an external lock. See, for example, U.S. Pat. No. 6,030,143 to Kreitzberg, U.S. Pat. No. 6,385,871 to Quarfordt, and U.S. Pat. No. 4,965,945 to Emrich.
As can be appreciated, excavating teeth are used often used under arduous conditions. The loads applied to the points, particularly with large mining buckets, can be very large, of various kinds, and continually shifting. It is important to maintain the lock in the defined passage during use so that the point is not lost. Loss of the point not only requires replacement of the point and causes premature wearing of the adapter, but may also damage downstream machinery intended to process the excavated material. Accordingly, the lock is usually fit tightly within the defined passage to inhibit its ejection or loss. The tight engagement can be caused by the insertion of a resilient tightening member in the passage, partially misaligned holes in the adapter and point, or close dimensioning between the holes and the lock. In the past, a large hammer has typically been needed to force the lock into and out of the passage. This tends to be an onerous and time-consuming task for the operator in the field, and exposes the worker to some risk.
There is a need in the industry for a lock that can be easily inserted into and out of the wear assembly without hammering, and yet can effectively hold the wear part in place even under severe conditions.